In conventional software systems, some transactions display data for the user in the form of a hierarchical list called a tree. The tree structure may appear on the left side of the transaction window and a corresponding list may be displayed in tabular form on the right side of the window.
FIG. 1 shows an example of a tree list displaying flight information. Display 10 includes tree list display area 11, which shows a tree list, and data display area 12, which shows flight data in tabular form. Displayed in tree list display area 11 are the elements of a tree list including supernode 13.1, upper nodes 14.1, 14.2, 14.3, nodes 15.1, and leaves 16. Supemode 13.1, upper nodes 14.1, 14.2. 14.3, nodes 15.1, and leaves 16 are organized hierarchically, with each leaf 16 being assigned to a particular node 15.1, each node 15.1 being assigned to a particular upper node 14.3, and each upper node 14.3 being assigned to a particular supernode 13.1. The hierarchy of the tree list is displayed in tree list display area 11. Supernodes 13.1, upper nodes 14.1, 14.2, 14.3, nodes 15.1, and leaves 16 may also be referred to herein as folders and/or files. The user can open or close folders in the tree by clicking on the triangles beside the tree nodes. Clicking on this triangle causes the corresponding branches in the tree to alternatively appear or disappear from view. Data display area 12 is bordered on the top by header display 17. Alternatively, header display 17 may be situated on the bottom of display area 12. Header display 17 includes attributes 18.1, which identify the characteristic displayed in the column underneath each attribute 18.1. Each row under each column includes value 19.1, which represents data corresponding to the attribute identified by attribute 18.1 of the column for the corresponding folder or file.
The set of attributes associated with a particular folder or file is called a line structure or field catalog. Therefore, the line structure displayed for each folder or file corresponds to the header being displayed in header display 17. In conventional software systems, tree lists are subject to the restriction that, for each node, the lines displayed on the right in tabular form must all have the same line structure. The display does not support different, individual line structures for each line. Technically, this restriction is based on the fact that, in conventional systems, only one field catalog may be assigned to a tree list. A field catalog is metadata that describes the line structure of the list. A field catalog may contain information about the list columns such as column headers, highlighting colors, key field flags, column width, the order in which information appears on the screen, whether or not the information is sorted and in which order (ascending or descending), flags for showing or hiding columns, etc.
Because of the restriction to one field catalog, tree lists containing lines with line structures that differ from each other either cannot be displayed at all or must use a work-around. A typical work-around assigns the field names to leaf nodes of the tree (at the deepest level in the hierarchy) and shows a single column of values on the right side of the screen.
FIG. 2 shows such a work-around for the display of technical information about a search engine running in a distributed environment. In FIG. 2, display area 10 is divided into two different areas for displaying information, namely tree list/header display area 21 and attribute display area 22. Tree list/header display area 21 includes vertical header 20, along with supernodes 13.2, upper nodes 14.1, 14.2, 14.3. nodes 15.2, 15.3, and leaves 16. Vertical header 20 includes attributes 18.2, 18.3, 18.4, 18.5, 18.6, arranged vertically. In attribute display area 22 in the row occupied by each attribute 18.2, 18.3, 18.4, 18.5, 18.6 is a corresponding value 19.2, 19.3, 19.4, 19.5, 19.6, 19.7, which is associated with the file or folder directly above vertical header 20, though alternative configurations may be possible. Due to the vertical orientation of vertical header 20, only one value is displayed in each row of attribute-display-area 22, and therefore less data is displayed in display 10.
For example, attribute 18.2 (active) of upper node 14.4 (the namesever running on port 8355) is displayed below and indented from upper node 14.4. This is similar to the display method for a node with respect to an upper node (for example, the relation between “queuserver: 8352” (upper node 14.5) and “queue” (node 15.2)). Attribute 18.2 (active) of upper node 14.4 (nameserver: 8355) is associated with (i.e., is displayed on the same row as) value 19.2 (yes). Attribute-display-area 22 includes only one column 23, which is named “Value”. Similarly, attribute 18.3 “active”, attribute 18.4 “read_accesscounter”, attribute 18.5 “write_accesscounter”, and attribute 18.6 “backup_accesscounter” of upper node 14.6 entitled “indexserver: 8351” are not columns in a row (as in FIG. 1) but are displayed vertically. This configuration for displaying attributes is similar to the display of nodes 15 2, 15.3 (e.g., node 15.2 “queue” and node 15.3 “index”) included within upper node 14.5 entitled “queueserver: 8352”. Attribute 18.3 entitled “active”, attribute 18.4 “read_accesscounter”, attribute 18.5 “write_accesscounter”, and attribute 18.6 “backup_accesscounter” of upper node 14.6 entitled “indexserver: 8351” correspond to value 19.3 “yes”, value 19.4 “119”, value 19.5 “2783”, value 19.6 “0”, respectively, in column 23 of attribute display area 22.
In order to circumvent the technical restrictions of the tree lists, headers 17 may be displayed as vertical headers 20, thereby occupying a large number of lines. This may make tree lists very long. The user may need to scroll down many pages to access information located in different parts of a tree list.
There thus is a need for an improved method of displaying tree lists.